What is the difference between an Excessive Heat Watch, Warning, or Advisory?

A common question that we get asked all the time is “what is the difference between an Excessive Heat Watch and Warning, and how do they differ from a Heat Advisory?” Below are the answers:

EXCESSIVE HEAT WATCH: An Excessive Heat Watch is issued when there is a potential for the heat index value to reach or exceed 110 degrees or 105 degrees within the next 24 to 48 hours.

EXCESSIVE HEAT WARNING: An Excessive Heat Warning is issued when the heat index value is expected to reach or exceed 110 degrees or 105 degrees within the next 12 to 24 hours. An Excessive Heat Warning may be issued for lower criteria if it is early in the season or during a multi-day heatwave.

HEAT ADVISORY: A Heat Advisory is issued when the heat index value is expected to reach 105 to 109 degrees (east of the Blue Ridge) or 100 to 104 degrees (west of the Blue Ridge) within the next 12 to 24 hours. A Heat Advisory may be issued for lower criteria if it is early in the season or during a multi-day heatwave.

Here are four safety recommendations from the National Weather Service to stay cool during heat waves: